Credit control may involve mechanisms that interact in real-time with accounts associated with end users, and may control or monitor the charges related to service usage associated with those end users' accounts. For example, credit control may involve checking whether credit is available for a given account, reserving credit, deducting credit from the end user account when service is completed, and/or refunding reserved credit that is not used. Credit control has particular applicability in the provision of network services, such as, for example, provision of cellular airtime in a cellular radio network, provision of multimedia data in a wired or wireless network, etc. Credit control may be implemented by a charging system (e.g., a credit control server) that monitors and controls charges related to service usage of end users, and that grants and/or denies credit authorizations to those end users, thus, enabling network service delivery to the end users.
RFC 4006, entitled “Diameter Credit-Control Application” (DCCA), provides a specification that can be used to implement real-time credit-control for a variety of end user services such as network access services, Session Initiation Protocol (SIP) services, messaging services, and download services. RFC 4006 provides a general solution to real-time cost and credit-control in charging systems.